As is known in the art, many systems require generating and monitoring voltages generated for a variety of different components on a common printed circuit board. One such system is a data storage system used to interface between a large host computer or server (collectively referred to herein as “host computer/servers”) and a bank of magnetic disk drives. The interface includes “front end” or host computer/server controllers (or directors) and “back-end” or disk controllers (or directors). The interface operates the controllers (or directors) in such a way that they are transparent to the host computer/server. That is, data is stored in, and retrieved from, the bank of disk drives in such a way that the host computer/server merely thinks it is operating with its own local disk drive. One such system is described in U.S. Pat. No. 5,206,939, entitled “System and Method for Disk Mapping and Data Retrieval”, inventors Moshe Yanai, Natan Vishlitzky, Bruno Alterescu and Daniel Castel, issued Apr. 27, 1993, and assigned to the same assignee as the present invention.
As is also known in the art, such a system typically includes a plurality of printed circuit boards having thereon the controllers. These controllers include a plurality of CPUs, DRAMs, ASICs as well as other integrated circuit chips. The CPUs typically require one level and time characteristics of voltages while each of the other ICS require still different levels of voltages.
One technique used to supply a voltage to the CPU is by the CPU generating a digital code, such as the VID code for setpoint control of a voltage regulator used to supply the voltage to the CPU. More particularly, a voltage regulator module (VRM) is used to provide the voltage for the CPU. The VRM is an electronic device that provides a microprocessor (or CPU) the proper supply voltage. The proper supply voltage is communicated by the microprocessor to the VRM at startup via a number of bits called a VID (voltage identificator). In particular, the VRM initially provides a standard supply voltage to the VID logic, which is the part of the processor whose only aim is to then send the VID to the VRM. When the VRM has received the VID identifying the required supply voltage, it starts acting as a voltage regulator, providing the proper voltage supply to the processor.
One technique used to provide different voltages to the different ICs is with a plurality of non-VRM circuits, such as a DC/DC point-of-load (POL) converter, one such non-VRM point-of-load converter for each IC voltage, each one of the point-of-loads providing a different voltage.